2009 Tacoma #4 misfire

[JCBELWOOD]

HELP! As the title says, it is a 2009 Tacoma, 2.7l 4 cylinder, runs terrible when cold (less than 150 degrees). Throwing P0304 (#4 cylinder misfire) code. So far I have replaced the #4 coil pack, all 4 spark plugs, cleaned the injectors & fuel rail, & swapped #4 injector to #1. The truck runs great after it gets up to operating temp, & the problem can only be duplicated after it sets all night. Thanks.

 

[ken_79-fj40]

Was the number 4 plug cleaner looking than the rest and do you hear gurgling in your heater core? If so it could be a slight head gasket leak. It was really common on cylinder 6 of the pre-08 4.0's and I have heard of a couple cases on 4 cylinders. My current V6 threw a misfire code a few weeks after I bought it with 121k on it. It would occasionally run rough at idle cold and that's what it was. I tried swapping coils first and once the code didn't change cylinders I pulled the plugs and number 6 was too clean. You would never know anything was wrong once it warmed up. Fortunately the Toyota dealer I bought the truck from covered the job in full. They did both sides, resealed the front of the motor, and it's been perfect since. I'm positive that's why it got traded in on a new one. The truck was spotless and over-maintained otherwise.

 

[buellfire]

Have you ever had the valves adjusted? Could be the valves are tight.

 

[JCBELWOOD]

ken-it is a 4 cylinder, the plug looked a little different
buellfire-it has the variable valve timing system, not sure if they can be adjusted.